Tens of thousands of people — including prominent mental health professionals — are arguing that Donald Trump has “a serious mental illness that renders him psychologically incapable” of being president.

The assertion was made in a petition drafted by former Johns Hopkins instructor John Gartner, who argues that the new leader of the free world displays clear symptoms of three personality disorders: narcissistic personality disorder, antisocial personality disorder, and paranoid personality disorder.

The letter, which was created last week, has amassed over 16,000 signatures.

And though it will almost certainly not result in Trump’s impeachment, it does bring some interesting questions into focus.

Namely: can a psychologist diagnose someone they’ve never met?

Gartner, who has previously diagnosed President Bill Clinton with “hypomanic temperament,” argues yes.

Though most mental health professionals adhere strictly to the Goldwater Rule – which unofficially keeps experts from diagnosing someone they have not examined personally – he said Trump’s public displays make him possible to diagnose from afar.

“We don’t need to interview Donald Trump to get reliable information,” he told Psychology Today. “We have a lot of data based on his actions.”

Steven Berglas, also a psychologist, disagrees. He thinks that Trump is unfit to be president, but not because he’s mentally ill.

“Donald Trump is a thoroughly inadequate human being,” Berglas said. But it’s impossible to tell if his public persona adequately reflects his true intentions and mental state without examining him personally.

“You cannot discern from public behavior whether a person’s behavior represents an authentic personality style or is choreographed.”

Still, that hasn’t stopped many professionals from trying. Here’s what 15 of them had to say about our president’s mental state:

“He’s so classic that I’m archiving video clips of him to use in workshops because there’s no better example of his characteristics.”
— George Simon, clinical psychologist specializing in manipulative behavior

“He’s very easy to diagnose. In the first debate, he talked over people and was domineering. He’ll do anything to demean others, like tell Carly Fiorina he doesn’t like her looks. ‘Your fired!’ would certainly come under lack of empathy. And he wants to deport immigrants, but (two of) his wives have been immigrants.”

— Charlotte Prozan, psychotherapist

“Donald Trump’s basic personality traits suggest a presidency that could be highly combustible….It is as if Trump has invested so much of himself in developing and refining his socially dominant role that he has nothing left over to create a meaningful story for his life.”

“The public rhetoric of Trumpism normalizes what therapists work against in our work: the tendency to blame others in our lives for our personal fears and insecurities and then battle these others instead of taking the healthier but more difficult path of self-awareness and self-responsibility. It also normalizes a kind of hyper-masculinity that is antithetical to the examined life and healthy relationships that psychotherapy helps people achieve. Simply stated, Trumpism is inconsistent with emotionally healthy living—and we have to say so publicly.”

“He consciously overrides the ‘truth’ because the ‘truth’ would be fraught with shame — the narcissist’s kryptonite. Clinical experts call this an overcompensation or a (necessary) distortion to maintain his (narcissistic) extraordinariness. In plain-speak it’s fiction — revisions of reality to keep the narcissist fully supplied with supreme specialness.”

“We’ve reached the point where we expect our politicians to behave like psychopaths. Trump’s ‘psychopathy,’ incidentally, is expressive in a less ‘compartmentalized’ form than that of most candidates, meaning he’s really more than a ‘political psychopath’ – he’s really just broadly, flat-out a psychopath.”

Some mental health experts are more concerned with the mental state of Trump’s fans who, despite the man’s proven and extensive record of lying, continue to stand up for his actions.

“For me, the compelling question is the psychological state of his supporters. They are unable or unwilling to make a connection between the challenges faced by any president and the knowledge and behavior of Donald Trump. In a democracy, that is disastrous.”